ss 



MELANOPSIS. Lamarch. 



'€en. Char. Univalve, subfasiform or turritec! ; 

 mouth oval, pointed above, emarginate be- 

 low ; outer lip sharp edged, entire, upper 

 part pressed against the spire ; inner lip 

 thick, tumid above ; columella plain, acute, 

 curved ; operculum coriacious. 



j\ GENUS of Fresh water shells lately established, and 

 oi Which there are several recent species ; tlie lower part 

 «f the mouth in some of them is produced into a ver)"^ 

 short be-ak, and in all it is more or less dilated ; the epi- 

 dermis is rather thick smooth, and a;enerally of a black- 

 ish green colour, as in most fresh water genera ; the 

 animal closes the mouth of its shell with a coriacious 

 operculum, that increases from a point situated near the 

 lower part of its inner edge ; it is rather partial to tem-- 

 perate climates, 



MELANOPSIS fusirormk 



TAB, CCCXXXIL— F%.^. 1 /o 1. 



Spec. Char. Fusiform, in the middle subcylln* 

 drical, smooth; mouth half the length of the 

 shelL 



i HIS species is liable to considerable variation In leng'tb^ 

 some specimens being much elongated, others ovate 

 and pointed. The shorter ones have most of the subcy- 

 lindrical form of AnciUa, and also a slight sinus towards 

 the u])per part of the outer lip, where it is applied to the 

 opposed callus, which is lara,est iu such ittdividuals. 

 Since there is a series ot these forms found iu the same 

 place, and as the mouth is constantly half a,s iw^ as the 



